1. Field of the Invention
The present invention relates to an electrically-operated actuator system such as the one capable of activating a movable member such as an air mix door, a mode switching door in a vehicle air conditioner, or the like.
2. Related Art
As disclosed in JP-A-H11-342724, an electrically-operated actuator is operated to an operational limit, for example, a mechanical motion-limiting member such as a stop to recognize a position thereof at the operational limit as a starting point for motion of the actuator. The operational angle of the actuator is controlled by using the starting point. Hereinafter, an operation in which the actuator is activated until it is stopped by the stop is referred to as an initialization.
However, the initialization is conducted whenever the actuator described in the above-described Japanese publication comes close to the starting point, so that the impact force is applied frequently to the electrically-operated actuator and the stop.
Therefore, the mechanical strength should be increased in both of them. This results in the growth in size of both of them and the rise in their manufacturing initial cost.
By the way, there is tendency that the number of vehicles has increased these days, which control electric power supply from a battery in the vehicle to electrical apparatuses in the vehicle and stop supplying electric power to them when a predetermined time has elapsed after the ignition switch was turned off, that is, while the vehicle is stopped or parked and the ignition switch is turned off, to reduce the consumption of dark current which flows in the electrical apparatuses.
Meanwhile, the electric actuator, which has a memory, also receives electrical supply from the battery, for memorizing the information regarding the starting point. The actuator will perform the initialization after power has been turned off because the information regarding the starting point is volatile or erased when the electric supply is stopped.
Therefore, the initializing process will be performed whenever the ignition switch is turned on, in a case when the battery is disconnected as well as in a case when the predetermined time has elapsed after the ignition switch is turned off because the information regarding the starting point is erased whenever the predetermined time has passed after the ignition switch is turned off because of the stop of power supply.
Consequently, the impact force will frequently be applied to the stop and the electrical actuator, and therefore, it is necessary to increase the strength of them which thereby increases the initial cost and need to make their size bigger.